Ocular manifestations and immunological profiles of thyroid eye disease with lacrimal gland enlargement.

INTRODUCTION

Thyroid eye disease (TED) is a prevalent autoimmune inflammatory condition in patients diagnosed with Graves' disease (GD). The lacrimal glands are implicated as an additional target organ of autoimmune reactions in TED, alongside orbital connective tissues. However, the underlying pathogenesis of lacrimal gland enlargement in TED and its associated symptoms and effective therapeutic strategies remain to be elucidated. This study aimed to investigate the ocular manifestations and immunological profiles of TED with lacrimal gland enlargement.

METHODS

This study collected patients diagnosed with TED, divided into the enlarged lacrimal gland (ELG) and the normal lacrimal gland (NLG) groups based on magnetic resonance imaging (MRI) measurement. Ocular manifestations, thyroid function tests, and immunological examinations of the peripheral blood were systematically compared between the two groups.

RESULTS

123 TED patients (NLG: ELG = 36: 87) were enrolled in this study. Patients in the ELG group exhibited worse proptosis, decreased tear film break-up time (TBUT), and increased Schirmer I test values, compared to the NLG group (P < 0.05), with no statistical difference in clinical activity score (CAS). Lacrimal gland enlargement in TED was accompanied by an elevation in thyroid peroxidase antibody (TPO-Ab) levels. Moreover, the proportions of CD8+ T cells and regulatory T (Treg) cells were remarkably elevated in the ELG group (P < 0.05). Correlation analyses demonstrated that serum TPO-Ab levels and Treg cell proportions were significantly correlated with lacrimal gland area. Further multivariate regression analyses confirmed that both TPO-Ab and Treg cells served as independent influencing factors for lacrimal gland enlargement in patients with TED.

CONCLUSIONS

TED patients with enlarged lacrimal glands exhibited worse proptosis, unstable tear film, and excessive tearing. TPO-Ab and Treg cells were positively correlated with lacrimal gland enlargement in TED. Furthermore, Treg cell frequency emerged as a predictive biomarker for lacrimal gland involvement in TED patients.